Sulfonates are widely used to impart water-solubility to hydrophobic molecules. However, the high polarity of the sulfonate groups in sulfonated molecules dominates their physical properties and precludes their ability to diffuse across cellular membranes. Thus, many sulfonated fluorescent dyes and potential therapeutic molecules cannot access intracellular locations. Furthermore, there are few useful protecting groups or prodrugs for sulfonates, as most sulfonate esters are highly reactive with nucleophiles, and those that are stable generally require harsh conditions for removal.